Trees are reactive organisms - everything they do is normal - it's not like they make choices. ;o)

Around this time of year, leaf loss in temperate deciduous trees is triggered by the days getting shorter. More accurately it is the increasing length of dark periods, but let's just say it's put into motion by a reduction in photoperiod, which is the amount of sunlight in one day. A chemical called phytochrome "measures' the photoperiod. When day length reaches a certain point, phytochrome 'signals' the tree to start preparing for winter. You could think of this as someone standing next to the tree with a stop watch, keeping track of how long each day was. Wavelengths of red light activate phytochrome and make this process possible - just another example of how light controls many plant life processes.

Deciduous trees normally perform one rather obvious task to prepare for winter. They drop their leaves. This is known as abscission. Keep in mind that red light activates phytochrome which, in turn, activates abscission. It all ties back to photoperiod. One of the first stages of abscission involves growing a layer of corky cells where the petiole (stem) of the leaf is attached to the tree. These cells will block the transport tunnels to the leaf so no water or nutrients can get in, and no sugars can get out.

As the abscission process develops normally, chlorophyll begins to breakdown and disappear. It will breakdown to where its molecular structure no longer reflects any portion of white light. Chlorophyll is constantly being broken down by sunlight; it can only absorb so much energy before its bonds break apart. During the spring and summer leaves are continually building new chlorophyll molecules, but rebuilding becomes impossible in autumn due to the abscission layer of corky cells. No water or nutrients can get into the leaf to make new chlorophyll.

Since all leaves contain carotenoids , we will see shades of yellow and orange once the chlorophyll has broken down. Leaves are always reflecting yellow light, we just can't see it until the reflected green light from the chlorophyll is gone.

Abscission also causes anthocyanins to form in some trees. Just before a tree produces the corky cells, many nutrients and sugars in the leaf will move from the leaf to the tree. This is known as translocation. The sugars and chlorophyll (green pigment) remaining in the leaf will break down in a different fashion since the nutrients, especially phosphorus, went into the tree. Anthocyanin pigments result and the leaf will reflect red or purple light.

Sorry to be so long winded, but the above is prolly closer to what YOU might think of as 'normal' for this time of year. The abscission of green leaves is likely a signal that something is not culturally pleasing to the tree. There are a number of cultural conditions that can cause green leaves to fall. A sudden cold snap or moving a tree to deep shade could cause it, as could a drought response resulting from over or under-watering, to name a few.

Al

No arguing with professor Al, but if it makes you feel any better, my containerized grafted dwarf peach tree dropped all its leaves gradually over the last few weeks. Half was blown away by the previous two hurricanes. The fallen leaves were overall green, but I could see subtle tints of orange and yellow. The nectarine tree, however, is grown in exact conditions yet has not abscissed but actually making new leaves.

I was also worried like you but given the supple stems and intact buds, I'll settle for wishful thinking that this is normal for this variety. We'll see next year!

By the way prof Al, how often would you water and fertilize (gritty mix) once all leaves have abscissed?

"... how often would you water and fertilize (gritty mix) once all leaves have abscissed?"

Minimally. When it's cool & leaves have fallen, I only water enough to insure the soil is not completely dry. Usually my 'watering' takes the shape of a shovel of snow heaped on the soil so it can slowly melt in - maybe every 4-8 weeks, depending on the plant & pot material. I use lots of terra cotta, in which plants obviously will want more water than when they're in plastic or vitrified pottery.

Al

Al, when is your book coming out? =)

Glad to hear everything is A-OK. As soon as I get a yard, I'm planting the darn thing in some good soil in the ground! I think my trees will be much happier there (is that a "duh" statement?).

Thank you both for your help! I love this place.

I bought my peach tree at Home Depot and I have let it stay in the container 15 gal. the soil around my home is awful all sandy! The leaves keep falling one or two at a time. I keep the tree in my lanie due to the extensive heat it gets the evening sun. I keep the soil damp not over watered, I check it on a daily basis and I see one or two leaves fallen. What must I do to prevent this, is it the heat so I give it more water please help!!